Method of manufacturing silicon carbide single crystal ingot

Abstract

The present invention provides a method including: a temperature raising step of raising a temperature in a crystal growing furnace with a silicon carbide raw material and a silicon carbide seed crystal arranged therein to a crystal growing temperature; a single crystal growing step of maintaining the crystal growing temperature and causing a silicon carbide single crystal to grow on the silicon carbide seed crystal; and a temperature lowering step of lowering the temperature in the crystal growing furnace from the crystal growing temperature to stop growth of the silicon carbide single crystal, in which the method further comprises, between the single crystal growing step and the temperature lowering step, a temperature lowering preparation step of maintaining the temperature in the crystal growing furnace at the crystal growing temperature and causing concentration of nitrogen gas in the crystal growing furnace to increase to be higher than concentration of nitrogen gas in the temperature raising step and in the single crystal growing step, and in which the concentration of the nitrogens gas in the crystal growing furnace in the temperature lowering step is higher than the concentration of the nitrogen gas in the temperature raising step and the single crystal growing step.

Description

BACKGROUND OF THE INVENTIONField of the Invention[0001]The present invention relates to a method of manufacturing a silicon carbide single crystal ingot using a sublimation recrystallization method.[0002]Priority is claimed on Japanese Patent Application No. 2017-246605, filed on Dec. 22, 2017, the content of which is incorporated herein by reference.Description of Related Art[0003]Silicon carbide (SiC) has a larger electric breakdown field than that of Silicon (Si) by a degree of magnitude and has a greater band gap by three times. Also, silicon carbide (SiC) has properties such as higher thermal conductivity than that of silicon (Si) by about three times. Applications of silicon carbide (SiC) to a power device, a high-frequency device, a high-temperature operation device, and the like have been expected.[0004]A silicon carbide single crystal is typically manufactured by a sublimation recrystallization method. The sublimation recrystallization method is a method in which gas such a...

AI Technical Summary

Benefits of technology

The invention provides a method for manufacturing silicon carbide single crystals that improves efficiency by shortening the time required for temperature lowering after growth of the crystal. By increasing the concentration of nitrogen gas in the crystal growing furnace, the method promotes endothermic reaction of nitrogen and reduces the time needed for temperature lowering. This results in improved production efficiency for silicon carbide single crystals.

Problems solved by technology

Therefore, it takes a long time to perform the temperature lowering step for cooling the silicon carbide single crystal from such a high-temperature state to room temperature, which makes it difficult to improve productivity.

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